authentication

authentication is a skill for Claude Code, Codex from jkaninda/okapi-skills. It costs 0 tokens per session (1,959 once invoked), scanned A, original, MIT.

JWT-based authentication for checking signed login tokens sent with API requests. JWTs are compact tokens that can carry claims such as a user's identity, role, issuer, and intended audience.

In plain words
What is it for?
Use it to protect routes with HMAC, RSA, or remote JWKS keys, accept tokens from headers or cookies, and pass selected user details such as email or role to handlers.
Why use it?
It verifies that tokens are valid and can enforce rules about who issued them, which service they target, and what claims they contain. Verified claims are then available in the request context.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one.

Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

agentmods
npx agentmods add skills/jkaninda/okapi-skills/authentication
Any agent
npx skills add jkaninda/okapi-skills --skill authentication
Clone the repo
git clone --depth 1 https://github.com/jkaninda/okapi-skills

Made for: Claude Code, Codex.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

agentmods badge for authentication

README.md
[![agentmods](https://agentmods.dev/badge/skills/jkaninda/okapi-skills/authentication.svg)](https://agentmods.dev/skills/jkaninda/okapi-skills/authentication)
Your own site
<a href="https://agentmods.dev/skills/jkaninda/okapi-skills/authentication"><img src="https://agentmods.dev/badge/skills/jkaninda/okapi-skills/authentication.svg" alt="Measured on agentmods" height="20"></a>
Per session 0 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,959 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
Origin original No closer match found in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5.1 $0.00000 $0.01959
Opus 5 $0.00000 $0.00979
Sonnet 5 $0.00000 $0.00392
Haiku 4.5 $0.00000 $0.00196

Measured 5d ago against content hash 9f2c99e8c659, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-06, from the pricing page.

Security

Grade A, and why

authentication scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 5d ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

authentication/SKILL.md · 199 lines

How it starts

The opening of the file, as written. The whole thing — 199 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Okapi Authentication & CORS

JWT Authentication

JWTAuth extracts the token, verifies the signature, optionally enforces claims, and stores claims in the context.

jwtAuth := okapi.JWTAuth{
    SigningSecret: []byte("supersecret"),   // HMAC (HS256/384/512)
    RsaKey:        publicKey,               // RSA (RS256/384/512)
    JwksUrl:       "https://issuer.example.com/.well-known/jwks.json",
    JwksFile:      jwks,                    // from okapi.LoadJWKSFromFile(...)

    Algorithms:  []string{"RS256", "ES256"}, // accepted signing algorithms
    Audience:    "my-api",                   // expected "aud"
    Issuer:      "https://issuer.example.com", // expected "iss"
    TokenLookup: "header:Authorization,cookie:jwt", // sources, tried in order

    ContextKey: "user",                      // store the full claims under this key
    ForwardClaims: map[string]string{        // copy selected claims into the store
        "email": "user.email",
        "role":  "realm_access.roles.0",
    },

    ClaimsExpression: "Equals(`email_verified`, `true`) && OneOf(`user.role`, `admin`, `owner`)",
    ValidateClaims:   func(c *okapi.Context, claims jwt.Claims) error { return nil },
    OnUnauthorized:   func(c *okapi.Context) error { return c.ErrorUnauthorized("Nope") },
}

api := o.Group("/api", jwtAuth.Middleware).WithBearerAuth()

Configure at least one verification mechanism: SigningSecret, RsaKey, JwksUrl, or JwksFile.

Field Notes
SigningSecret []byte HMAC key. Supersedes the deprecated SecretKey.
RsaKey *rsa.PublicKey RSA public key.
JwksUrl string Remote JWKS endpoint for key discovery.
JwksFile *Jwks Static JWKS from file or base64 (okapi.LoadJWKSFromFile).
Algorithms []string Accepted algorithms. Defaults to RS256, HS256, ES256. Supersedes the deprecated single-valued Algo.
Audience / Issuer Validated aud / iss claims.
TokenLookup string Comma-separated source:name list; the first non-empty hit wins. Default header:Authorization.
ContextKey string Key holding the full jwt.MapClaims.
ForwardClaims map[string]string contextKey -> claim.path (dot notation, numeric indices allowed).
ClaimsExpression string Expression DSL (below).
ValidateClaims func(*Context, jwt.Claims) error Custom validation; supersedes the deprecated ValidateRole.
OnUnauthorized HandlerFunc Custom response for any auth failure.

Read the full file on GitHub · 199 lines

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. 5d ago First seen · 199 lines · 0 tokens per session scan A 9f2c99e8c659

Subscribe to this mod's changes

authentication is a skill published in the GitHub repository jkaninda/okapi-skills (3 stars, last pushed 20d ago), licensed MIT. It costs nothing until one of its globs matches a file; then it loads 1,959 tokens. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-31.

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